JPH04253088A - Liquid crystal projector - Google Patents

Abstract

PURPOSE:To improve the resolution of a liquid crystal panel where picture elements are arrayed in two dimensions by compensating the missing of an image at black matrix parts between adjacent picture elements. CONSTITUTION:In the processor wherein switching elements are formed corresponding to the respective picture elements and a liquid crystal panel which controls the transmission of light is mounted, two liquid crystal panels (6) and (9) where the picture elements (6a) and (9a) are formed at the same pitch are arranged shifting by a 1/2 pitch at least vertically. A video signal processing circuit (11) drives one liquid crystal panel with an odd-field signal and the other liquid crystal panel with an even-field signal and transmitted light beams of both the liquid crystal panels are put one over the other to form a projection image. Thus, the image wherein matrix parts between the picture elements of one liquid crystal panel are compensated with the transmitted light of the other liquid crystal panel is obtained.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type liquid crystal projector, and more particularly to a liquid crystal projector with improved resolution.

0002

[Prior Art] Recently, projectors that can produce large images with a small bulk have been widely used, and are used not only for business use to project materials during meetings and lectures as enlarged images on a screen, but also for home use compared to conventional cathode ray tubes. It has also come to be used as a substitute for commercial television. In particular, a liquid crystal projector that uses a liquid crystal panel as a member to control light transmission has the advantage that although it can provide an enlarged image, the flatness of the liquid crystal panel allows it to be made very small as a device. It has been attracting attention recently.

[0003] The liquid crystal panel used in this type of equipment is
Since it uses the principle of applying a voltage to the liquid crystal to control the transmission of light, nonlinear elements such as TFTs (thin film transistors) and MIMs (thin film diodes) are used to control the voltage applied to the liquid crystal for each picture element. is provided, and this nonlinear element selects a picture element for display and creates a state in which light transmission is controlled by inputting an image data signal to the selected picture element.

By the way, in the liquid crystal panel described above, signal lines for supplying picture element selection signals and image data signals to the nonlinear elements provided for each picture element are formed using gaps between adjacent picture elements. ing. When an image data signal for projection is input, a voltage for the signal is applied not only to the selected picture element but also to the above signal line, and although it is an extremely thin line, a common line facing the signal line is applied. A voltage is also applied to the liquid crystal between the electrodes. Even if the result is not sufficient, the liquid crystal to which the voltage is applied as described above responds to light more than the liquid crystal to which no voltage is applied, causing deterioration in image quality. In order to prevent such deterioration in image quality and to increase contrast by blocking the influence of excess light seeping out from selected picture elements, a black matrix method is used in which the gaps between picture elements are covered with a black mask. It has been adopted.

[0005]

[Problems to be Solved by the Invention] In the conventional liquid crystal projector described above, a black matrix is formed on the mounted liquid crystal panel, which reduces the pixel area accordingly, making it difficult to enlarge a small image on the liquid crystal panel surface. In addition to the dispersion of the amount of light due to the presence of a large amount of light, the reduction in the amount of light described above is a cause of deterioration of image quality. Furthermore, since the image is enlarged and projected onto the screen, the shadow of the black matrix portion becomes noticeable in the projected image, which also reduces the quality of the projected image.

[0006] The present invention has been made in view of the above points, and an object of the present invention is to provide a liquid crystal projector that compensates for the drawbacks of the black matrix without impairing contrast and has high resolution characteristics. Furthermore, the present invention provides a liquid crystal projector capable of forming color projected images.

[0007]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides a projection type liquid crystal projector that includes:
A first liquid crystal panel in which picture elements are two-dimensionally arranged at a predetermined pitch, and a second liquid crystal panel that has the same pitch as the first liquid crystal panel and is optically arranged in a positional relationship shifted by 1/2 pitch in the vertical direction. panel, the transmitted light of the first liquid crystal panel and the second liquid crystal panel.
A liquid crystal projector is constructed by providing an optical system for projecting transmitted light from a liquid crystal panel in a superimposed manner, and a video signal processing circuit for inputting an odd field signal to the first liquid crystal panel and an even field signal to the second liquid crystal panel. Configure. Further, the first liquid crystal panel and the second liquid crystal panel are formed by arranging the three primary colors of R, G, and B on the same panel. Further, the first liquid crystal panel and the second liquid crystal panel have R,
The three primary colors G and B are arranged in pairs to complement the picture element gaps.

[0008]

[Function] In a liquid crystal projector, the position of the picture element is 1/
By transmitting light emitted from a light source through two liquid crystal panels that are shifted by two pitches and superimposing them, it is possible to form an image without making the shadow of the black matrix stand out even in an enlarged image. Furthermore, since one is driven with an odd field signal and the other is driven with an even field signal, a clear image can be obtained.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, inside the cabinet of the projector, a half mirror (3) is arranged on the optical path of white light emitted from a light source (1) via a filter (2) for extracting light in a desired wavelength range. The light from the light source (1) is divided into two and projected onto two liquid crystal panels to be described later. A portion of the light split by the half mirror (3) has its optical path adjusted by the total reflection mirror (4), and then is projected onto the first liquid crystal panel (6) via the condenser lens (5). The other part of the light split by the half mirror (3) also has its optical path adjusted by the total reflection mirror (7), and then condensed by the condenser lens (8).
) is projected onto the second liquid crystal panel (9).

[0010] Here, the first liquid crystal panel (6) and the second
Both liquid crystal panels (9) have picture elements (6a) and (6) arranged at the same pitch in the horizontal and vertical directions, as shown in FIG.
b) is placed. However, in each liquid crystal panel, picture elements are formed such that the even-numbered horizontal line 2n is shifted by 1/2 pitch in the horizontal direction from the odd-numbered horizontal line 2n+1. Each picture element is provided with a nonlinear element, such as a TFT, as a switching element for selecting the picture element, as has been conventionally implemented as an active matrix driven liquid crystal. Usually, a transparent electrode forming a picture element is connected to the drain of the TFT, and voltage application to this transparent electrode is controlled by the TFT, and the other common electrode facing the liquid crystal layer drives the liquid crystal layer. A voltage is applied.

In each of the liquid crystal panels described above, wiring for the source bus line and gate bus line of the TFT is formed in the gap between adjacent picture elements of the transparent substrate on which the picture elements are formed. On the other hand, on the transparent substrate side on which the common electrode was formed,
A common electrode made of a transparent electrode is formed, and a black insulator that blocks light is formed as a black matrix at a position corresponding to the gap between the adjacent picture elements. On the substrate on the common electrode side, a filter for coloring is formed in the picture element area surrounded by this black matrix. In this filter, three primary colors, for example R, G, and B, are arranged in a delta shape on the same panel surface. The first liquid crystal panel (6) and the second liquid crystal panel (9) in which the picture elements are arranged at the same pitch are arranged so that the picture elements (6a) and (9a) are optically arranged as shown in FIG. They are arranged with a 1/2 pitch shift in the vertical direction, and a part of the horizontal black matrix of one liquid crystal panel is covered by the picture elements of the other liquid crystal panel. That is, both liquid crystal panels (6
) and (9), an image in which the black matrix portion is complemented can be obtained. In FIG. 1, the half mirror (10) serves to combine the light that has passed through the first liquid crystal panel (6) and the second liquid crystal panel (9), and further directs the combined light to the lens system. The image is magnified by a lens system and projected onto a screen.

[0012] The first liquid crystal panel (6) and the second liquid crystal panel (9) are each connected to a video signal processing circuit (11) for image formation, and the TFTs are switched by the video signal to control the light source (1). Controls the transmission of light from. However, when inputting video signals, the first liquid crystal panel (6)
As described above, the picture elements of the second liquid crystal panel (9) and the second liquid crystal panel (9) are arranged with the picture elements shifted by 1/2 pitch, so in order to efficiently improve the resolution of the projected image, the video signal processing circuit (1
1), the odd field signal is input to the first liquid crystal panel (6), the even field signal is input to the second liquid crystal panel (9), and the light transmitted through each liquid crystal panel is superimposed via the optical system. A color projected image is formed by further enlarging the image and projecting it onto a screen.

In the above embodiment, R, G, B are displayed on the same panel surface.
The explanation has been given of a case in which a projection is configured using two liquid crystal panels that form three primary color filters.
, B, and a liquid crystal panel in which filters are arranged for each of these three primary colors can also be applied. In such a liquid crystal projection, another liquid crystal panel with picture elements shifted by 1/2 pitch is provided for each color liquid crystal panel in the same manner as in the above embodiment, and each color passes through two liquid crystal panels. By further superimposing the light through an optical system, a color image is formed as a projected image on the screen. In both this embodiment and the above embodiments, the size of the picture elements of the first liquid crystal panel and the second liquid crystal panel is not limited to approximately 1/2 of the pitch as shown in FIG. If it is larger than 2, the amount of light generated by the data signal at the corresponding picture element increases, making it possible to form a brighter image.

[0014]

As described above, according to the present invention, it is possible to reduce the visibility of the shadow of the black matrix formed for contrast improvement etc. in an enlarged projected image,
It is possible to form a projection image of excellent quality with improved resolution, and eliminates the drawbacks of using a liquid crystal panel.
The range of use of the liquid crystal projector can be further expanded.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of a liquid crystal projector according to the present invention.

FIG. 2 is a diagram showing the pixel arrangement relationship of two liquid crystal panels used in the same example.

FIG. 3 is a picture element arrangement diagram of one liquid crystal panel used in the same example.

[Explanation of symbols]

1. Light source 6 First liquid crystal panel 9 Second LCD panel 10 Half mirror 11 Video signal processing circuit

Claims (3)

[Claims] 1. A liquid crystal projector that forms a projected image of an image formed on a liquid crystal panel surface, comprising: a first liquid crystal panel in which picture elements are two-dimensionally arranged at a predetermined pitch; A second liquid crystal panel is arranged in a positional relationship optically shifted by 1/2 pitch in the vertical direction with respect to the first liquid crystal panel, and the transmitted light of the first liquid crystal panel and the transmitted light of the second liquid crystal panel are A liquid crystal projector comprising: an optical system that projects images in a superimposed relationship; and a video signal processing circuit that inputs an odd field signal to the first liquid crystal panel and an even field signal to the second liquid crystal panel. 2. The liquid crystal projector according to claim 1, wherein the first liquid crystal panel and the second liquid crystal panel have three primary colors of R, G, and B arranged in each panel. 3. The liquid crystal projector according to claim 1, wherein the first liquid crystal panel and the second liquid crystal panel are provided as a pair for each of the three primary colors R, G, and B.